Is the quality of therapeutic collaboration associated with the assimilation of problematic experiences progress? A comparison of two cases.

OBJECTIVE: How are collaborative interactions associated with clients' progress in therapy? This study addressed this question, by assessing the quality of therapeutic collaboration and comparing it passage by passage with the clients' assimilation of problematic experiences in two cases of major depression treated with Cognitive Behavioral Therapy, one recovered and one improved-but-not-recovered. METHOD: We used the Therapeutic Collaboration Coding System to code collaborative work and the Assimilation of Problematic Experiences Scale (APES) to rate clients' progress. In both cases, for the distribution of specific collaborative therapeutic exchanges, we tested for the difference of empirical means between lower and higher APES levels. RESULTS: Both cases progress in APES, but in contrast with Annie (Improved-but-not-recovered), Kate (Recovered) achieved higher levels of change in last sessions. In addition, we found significant differences in the types of collaborative therapeutic exchanges associated with lower and higher APES levels. CONCLUSION: Ambivalent therapeutic exchanges distinguished the recovered case from the not recovered case highlighting a source of difficulties in facilitating therapeutic change in CBT. In addition, observations in these cases supported the theoretical suggestion that supporting interventions would be better accepted at lower APES levels, whereas challenging interventions would be better accepted at higher APES levels.

Therapist's interventions immediately after exceeding the client's therapeutic zone of proximal development: A comparative case study.

OBJECTIVE: When therapists' proposals are too demanding exceeding clients' readiness to move into change, clients may resist advancing. We aimed to understand how a therapist behaved immediately after the client resisted advancing into change within Cognitive-Behavioral Therapy. METHODS: We analyzed a recovered and an unrecovered case, both with Major Depression, and followed by the same therapist. Through the Therapeutic Collaboration Coding System, we analyzed 407 exchanges of interest. RESULTS: In both cases, clients resisted more in advancing at intermediate sessions, mainly by the therapist's challenges to raise insight and debate cognitive beliefs in the recovered case, and to seek experiential meanings in the unrecovered case. Immediately after clients resisted advancing, the therapist tended to insist on challenging them in the same direction. In the recovered case, the therapist did so continually throughout the therapy, sometimes balancing between insisting or stepping back. In the unrecovered case, the therapist insisted on challenging, but mostly at the final session. Occasionally, the therapist insisted on challenging, and clients resisted over consecutive exchanges. CONCLUSION: Our results reinforce that to enact progress and change clients need to be pushed into change, however it requires therapists' skillful assessment of clients' tolerance to move in time.

A dependência no autocuidado nas famílias clássicas de uma freguesia do concelho de Coimbra: Um contributo para a intervenção dos enfermeiros de reabilitação / Dependence on self-care in classic families in a parish in the municipality of Coimbra: A contribution to the intervention of rehabilitation nurses

As alterações demográficas do último século, que se traduziram na alteração significativa das pirâmides etárias, refletindo o envelhecimento da população, vieram colocar às famílias e à sociedade, desafios a vários níveis. O envelhecimento da população e o aumento da prevalência das doenças crónicas e incapacidades, gera dependência no autocuidado. Investigar modelos assistenciais eficazes, que se traduzam em funcionalidade e manutenção da autonomia da pessoa, constitui um desafio. O processo de cuidados dos Enfermeiros Especialistas em Enfermagem de Reabilitação tem como foco central o autocuidado, com o intuito principal de capacitar a pessoa para o seu desempenho de forma autónoma. A finalidade deste estudo é conhecer a dependência no autocuidado das pessoas dependentes integradas nas famílias clássicas da união das freguesias de São Martinho do Bispo e Ribeira de Frades. Esta investigação está inserida num estudo de natureza quantitativa, descritiva simples, de base populacional, do tipo transversal, com recurso a uma amostragem probabilística. Para a avaliação da dependência no autocuidado, utilizou-se o formulário intitulado ?Famílias que integram dependentes no autocuidado?. Para a recolha de dados foi cumprido um esquema específico, programado para dois momentos, num contato porta a porta. Após o términus da recolha dos dados procedeu-se a uma análise estatística descritiva. Numa amostra de 387 famílias clássicas identificou-se que 11,1% integram uma pessoa dependente no domicílio. Relativamente ao perfil dos 35 prestadores de cuidados, são maioritariamente mulheres, com uma média de idades de 66 anos, casados e reformados. As 37 pessoas dependentes avaliadas são, na sua maioria, mulheres, idosos, reformados, casados, com o primeiro ciclo do ensino básico. Os domínios do autocuidado inerentes à higiene pessoal, uso de cadeira de rodas e toma da medicação são aqueles que se encontram mais frequentemente comprometidos, enquanto que os domínios inerentes à mobilidade são os menos afetados. A maior parte das pessoas dependentes necessita de ajuda do prestador de cuidados, prevendo-se que esta realidade se vá intensificar com o envelhecimento populacional, com consequências a nível da exigência dos cuidados, tanto a nível familiar, como profissional.

Face-to-Face Clinical Practice Under COVID-19 Pandemic: How Psychotherapists Describe Their Experiences.

Driven by the theory-building around the role of the non-verbal components to communication, we aimed to understand how therapists experience the therapeutic process using a facial mask. The empirical evidence of the power of non-verbal communication to engage therapists and clients in therapeutic work, develop a positive and collaborative relationship between them, and display empathy is quite large. A mixed-methods approach was adopted, drawing from the therapists' participation in an online survey. A sample of 137 psychotherapists with different therapy orientations and years of clinical practice participated in the study. Therapists conducted face-to-face therapy wearing face masks with existing and/or new clients. We performed an exploratory analysis, using descriptive statistics, to explore the psychotherapists' evaluations regarding perceived impact of face masks on different therapy quality dimensions. In a complementary rationale, we analyzed the therapists' perspectives on their experience wearing face masks using the thematic analysis methodology. Results show that among 137 psychotherapists, 114 were attending both existing and new clients, whereas only 13 were seeing exclusively existing clients and 10 were working exclusively with new clients. Despite no major differences were found between conditions regarding the perceived impact of face masks on different therapy quality dimensions and strategies adopted, the qualitative analysis allowed us to expand the quantitative results and deepen understanding of psychotherapists' experience. Based on general and typical patterns, we propose two distinct models to describe the therapist's experiences narrative when working with existing or new clients wearing face masks. Based on the results, we propose some recommendations to clinical practice in similar conditions.

Therapist's actions after therapeutic collaboration breaks: a single case study.

Aim: This study analyzes how a therapist contributed to therapeutic collaboration reestablishment by describing his actions after therapeutic collaboration breaks in a recovered completer clinical case. Method: Data was collected from a narrative therapy case with the diagnosis of depression spanning 19 sessions. We identified sequences in which therapeutic collaboration breaks were re-established (or not) through the Therapeutic Collaboration Coding System. We analyzed the therapist's actions after the therapeutic collaboration breaks through Conversation Analysis. Results: Typically, the therapist maintained the action that preceded the therapeutic collaboration break. When he did so by proposing a new meaning to the client's experience or by highlighting the client's agency, the therapeutic collaboration was usually re-established; however, when he did so by guiding or making exploratory questions to deepen the client's experience, the therapeutic collaboration was usually not re-established. When the therapist retreated from his previous action, the therapeutic collaboration tended to be re-established, mainly when he reflected the client's previous turn. Conclusion: This study suggests that more important than maintaining or retreating from the previous action is how the therapist does so. The therapist's actions of acknowledging the client's experience and agency contributed to therapeutic collaboration reestablishment.

Microplastics do not affect standard ecotoxicological endpoints in marine unicellular organisms.

In this study, the acute toxicity of microplastics (MPs) on unicellular organisms as marine decomposers and microalgae was assessed, by evaluating standards endpoints included in International Standard Organization (ISO) protocols. The bacteria Vibrio fischeri and the diatom Phaeodactylum tricornutum were exposed to different sizes (1-500 µm) of polyethylene MPs in order to evaluate bioluminescence inhibition and microalgal growth. No acute toxicity was found on bacteria or microalgae in an order of magnitude above environmentally relevant concentrations, suggesting that tested MPs did not affect the investigated biological processes. In conclusion, standard ecotoxicological endpoints are not sufficiently sensitive to assess the potential effects of MPs on decomposers and primary producers, conversely to nanoplastics. These findings highlight that the current approach for MP risk assessment in unicellular species should be revised, by providing alternative endpoints to be included in standardized protocols, able to monitor the fate and biological effects of MPs.

Changes in protein expression in mussels Mytilus galloprovincialis dietarily exposed to PVP/PEI coated silver nanoparticles at different seasons.

Potential toxic effects of Ag NPs ingested through the food web and depending on the season have not been addressed in marine bivalves. This work aimed to assess differences in protein expression in the digestive gland of female mussels after dietary exposure to Ag NPs in autumn and spring. Mussels were fed daily with microalgae previously exposed for 24 h to 10 µg/L of PVP/PEI coated 5 nm Ag NPs. After 21 days, mussels significantly accumulated Ag in both seasons and Ag NPs were found within digestive gland cells and gills. Two-dimensional electrophoresis distinguished 104 differentially expressed protein spots in autumn and 142 in spring. Among them, chitinase like protein-3, partial and glyceraldehyde-3-phosphate dehydrogenase, that are involved in amino sugar and nucleotide sugar metabolism, carbon metabolism, glycolysis/gluconeogenesis and the biosynthesis of amino acids KEGG pathways, were overexpressed in autumn but underexpressed in spring. In autumn, pyruvate metabolism, citrate cycle, cysteine and methionine metabolism and glyoxylate and dicarboxylate metabolism were altered, while in spring, proteins related to the formation of phagosomes and hydrogen peroxide metabolism were differentially expressed. Overall, protein expression signatures depended on season and Ag NPs exposure, suggesting that season significantly influences responses of mussels to NP exposure.

Changes in metallothionein transcription levels in the mussel Mytilus galloprovincialis exposed to CdTe quantum dots.

Quantum dots (QDs) are a class of engineered nanoparticles (ENPs) with several biomedical, industrial and commercial applications. However, their metabolism and detoxification process in aquatic invertebrates and environmental health hazards remain unclear. This study investigate the transcriptional changes of metallothioneins (MTs) isoforms (mt10IIIa and mt20IV) induced by CdTe QDs, in comparison with its dissolved counterpart, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and to the same Cd concentration (10 µg Cd L-1) of dissolved Cd for 14 days and mt transcription levels were measured by real time quantitative PCR (qPCR). Tissue specific mt transcription patterns were observed in mussels exposed to both Cd forms, wherein the gills were a more sensitive organ compared to the digestive gland. No significant changes were observed in mt10IIIa transcription levels in mussels exposed to both Cd forms. In contrast, transcription of mt20IV was tissue and exposure time dependent, with higher mt20IV mRNA levels in mussels exposed to QDs and dissolved Cd when compared to unexposed mussels. Multivariate analysis indicates particle-specific effects after 14 days of exposure and a dual role of MTs in the QD metabolism and in the protection against oxidative stress in mussels exposed to Cd-based ENPs.

Metal interactions between the polychaete Branchipolynoe seepensis and the mussel Bathymodiolus azoricus from Mid-Atlantic-Ridge hydrothermal vent fields.

The vent blood-red commensal polynoid polychaete Branchipolynoe seepensis is commonly found in the pallial cavity of the vent mussel Bathymodiolus azoricus, the dominant bivalve species along the Mid-Atlantic-Ridge (MAR) and is known to be kleptoparasitic. Mussels were collected from three hydrothermal vent fields in the MAR: Menez Gwen (850 m depth, MG2, MG3 and MG4), Lucky Strike (1700 m depth, Montségur-MS and Eiffel Tower-ET) and Rainbow (2300 m depth). Polychaetes were absent in all Menez Gwen vent mussels, while the highest percentage was detected in mussels from Lucky Strike, where more than 70% of the mussels had at least one polychaete in their mantle cavity, followed by Rainbow with 33% of mussels with polychaetes. Total metal concentrations (Ag, Cd, Co, Cu, Fe, Mn, Ni and Zn) were determined in polychaetes whole body and in the mussel tissues (gills, digestive gland and mantle). To understand the possible metal interactions between symbiont and host, the activity of antioxidant defence (catalase (CAT), metallothioneins (MTs)), biotransformation enzymes (glutathione-s-transferases (GST)) activities and lipid peroxidation (LPO) were determined in polychaete whole soft tissues and in mussel tissues (gills, digestive gland and mantle). Metal concentrations in polychaetes and mussels tissues indicated that the accumulation patterns were species specific and also influenced by, and possibly dependent upon, the inter- and intra-variation of vent physico-chemistry between hydrothermal fields. Despite not detecting any strong correlations between metal and enzymes activities in polychaetes and mussels, when in presence of polychaetes, mussels presented less metal concentrations in the gills and digestive gland and lower activity of enzymatic biomarkers. This leads to infer that the polychaete plays a role on the detoxification process, and the interaction between the polychaete mussel association is probably an adaptation to metals concentrations at the vent sites.

Environmental hazard assessment of a marine mine tailings deposit site and potential implications for deep-sea mining.

Portmán Bay is a heavily contaminated area resulting from decades of metal mine tailings disposal, and is considered a suitable shallow-water analogue to investigate the potential ecotoxicological impact of deep-sea mining. Resuspension plumes were artificially created by removing the top layer of the mine tailings deposit by bottom trawling. Mussels were deployed at three sites: i) off the mine tailings deposit area; ii) on the mine tailings deposit beyond the influence from the resuspension plumes; iii) under the influence of the artificially generated resuspension plumes. Surface sediment samples were collected at the same sites for metal analysis and ecotoxicity assessment. Metal concentrations and a battery of biomarkers (oxidative stress, metal exposure, biotransformation and oxidative damage) were measured in different mussel tissues. The environmental hazard posed by the resuspension plumes was investigated by a quantitative weight of evidence (WOE) model that integrated all the data. The resuspension of sediments loaded with metal mine tails demonstrated that chemical contaminants were released by trawling subsequently inducing ecotoxicological impact in mussels' health. Considering as sediment quality guidelines (SQGs) those indicated in Spanish action level B for the disposal of dredged material at sea, the WOE model indicates that the hazard is slight off the mine tailings deposit, moderate on the mine tailings deposit without the influence from the resuspension plumes, and major under the influence of the resuspension plumes. Portmán Bay mine tailings deposit is a by-product of sulphide mining, and despite differences in environmental setting, it can reflect the potential ecotoxic effects to marine fauna from the impact of resuspension of plumes created by deep-sea mining of polymetallic sulphides. A similar approach as in this study could be applied in other areas affected by sediment resuspension and for testing future deep-sea mining sites in order to assess the associated environmental hazards.

Coompreendendo a Cárie Dental / Understanding the dental carie

Introdução: a cárie dental é uma doença infecciosa de caráter multifatorial e por sua grande incidência na sociedade moderna, é considerada ainda hoje um problema de saúde pública. Objetivo: este artigo visa apresentar, através de uma revisão bibliográfica, a organização de informações sobre a doença cárie, sua incidência, a influência da cárie na autoestima das pessoas, seus fatores imunológicos e microbiológicos, bem como a promoção de sua prevenção. Método: trata-se de um estudo de revisão bibliográfica. Resultados e Discussão: vários aspectos levantados durante esta pesquisa demonstram que, apesar de ser amplamente estudada e haverem postulados desde 1960 sobre a doença cárie, ainda é necessário um intenso trabalho Recebido em: 08/11/2017 para que sua incidência diminua, principalmente em países e regiões mais pobres. Conclusão: o conhecimento sobre a cárie é importante para o planejamento odontológico de seu tratamento, os quais auxiliarão estudantes, cirurgiões dentistas e demais membros da comunidade, na busca da prevenção da referida patologia.

Introduction: dental caries is an infectious disease of multifactorial character and for its great impact on modern society, is regarded today as a public health problem. Objective: this paper aims to present concepts about the caries disease, its focus, the influence of tooth decay in people's self-esteem, its immunological and microbiological factors, as well as the promotion of its prevention. Method: the sutudy was done through a bibliographical review. Results and Discussion: various aspects raised during this study shows that, despite being widely studied and they had been postulated since 1960 on the caries disease, it is still necessary to work greater for its incidence decrease, mainly in poorer countries and regions. This article is a completely bibliographical research and seeks to bring to the odontology scholars, a tool for the study of the knowledge of dental caries. Conclusion: knowledge about caries is important for the dental planning of its treatment, which will help students, dental surgeons and other members of the community, in the search for the prevention of this pathology.

Manter o aleitamento materno após o regresso ao trabalho práticas desenvolvidas pelos enfermeiros especialistas em enfermagem de saúde infantil e pediatria, que ajudam as mães a conciliar a amamentação e o trabalho / Maintaining breastfeeding after returning to work practices developed by specialist nurses in child health nursing and pediatrics, which help mothers to reconcile breastfeeding and work

Apesar das várias iniciativas desenvolvidas no sentido da promoção da amamentação, as taxas de aleitamento materno continuam abaixo das recomendadas, verificando-se um decréscimo acentuado após o regresso das mães ao trabalho (DGS, 2014). Este estudo procurou conhecer as medidas promotoras da amamentação que os enfermeiros dos cuidados de saúde primários, Especialistas em Enfermagem de Saúde Infantil e Pediatria, desenvolvem no sentido de apoiarem as mães que trabalham a continuarem a amamentar e identificar as intervenções promotoras da amamentação desenvolvidas pelos enfermeiros junto das mães, a nível da comunidade, na família, nos locais de trabalho, nas creches e nos seus próprios locais de trabalho. Desenvolveu-se um estudo descritivo e transversal, seguindo uma metodologia qualitativa, junto de 13 enfermeiros Especialistas em Enfermagem de Saúde Infantil e Pediatria que trabalham em Centros de Saúde do Agrupamento de Centros de Saúde do Baixo Mondego. Para a colheita de dados utilizou-se uma entrevista semiestruturada, cuja aplicação decorreu entre 2 de junho e 6 de julho de 2015. No tratamento da informação recorreu-se à análise de conteúdo de Laurence Bardin. Os resultados evidenciaram que os enfermeiros estão despertos para a necessidade de promover a manutenção da amamentação após o regresso das mães ao trabalho, sendo que desenvolvem, nesse sentido, várias intervenções, junto das mães, pais, avós e crianças, predominantemente nas consultas de enfermagem. Há contudo, outros locais onde as intervenções de enfermagem deviam chegar, nomeadamente, creches, entidades patronais e sociedade em geral, com vista a reduzir o desmame precoce motivado pelo regresso das mães ao trabalho.

Tissue specific responses to cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis.

In recent years, Cd-based quantum dots (QDs) have generated interest from the life sciences community due to their potential applications in nanomedicine, biology and electronics. However, these engineered nanomaterials can be released into the marine environment, where their environmental health hazards remain unclear. This study investigated the tissue-specific responses related to alterations in the antioxidant defense system induced by CdTe QDs, in comparison with its dissolved counterpart, using the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd for 14 days at 10 µgCd L(-1) and biomarkers of oxidative stress [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (total, Se-independent and Se-dependent GPx) and glutathione-S-transferase (GST) activities] were analyzed along with Cd accumulation in the gills and digestive gland of mussels. Results show that both Cd forms changed mussels' antioxidant responses with distinct modes of action (MoA). There were tissue- and time-dependent differences in the biochemical responses to each Cd form, wherein QDs are more pro-oxidant when compared to dissolved Cd. The gills are the main tissue affected by QDs, with effects related to the increase of SOD, GST and GPx activities, while those of dissolved Cd was associated to the increase of CAT activity, Cd accumulation and exposure time. Digestive gland is a main tissue for accumulation of both Cd forms, but changes in antioxidant enzyme activities are smaller than in gills. A multivariate analysis revealed that the antioxidant patterns are tissue dependent, indicating nano-specific effects possibly associated to oxidative stress and changes in redox homeostasis.

Adsorbed Mass of Polymers on Self-Assembled Monolayers: Effect of Surface Chemistry and Polymer Charge.

The adsorbed mass of polymers on surfaces with different chemistry is presented, and the related adsorption mechanism is discussed. Strong and weak polyelectrolytes of negative and positive charge are studied, as well as an uncharged polymer. Self-assembled monolayers of alkanethiols on gold are used in reflectometry and quartz crystal microbalance (QCM-D) experiments as adsorbing substrates bearing different terminal moieties, namely, methyl, hydroxyl, carboxyl, and amine groups. The various polymer-surface combinations allow the systematic investigation of the role of surface chemistry and polymer charge on adsorbed amount. Interactions of different nature and range drive polymer adsorption: the measured adsorbed amounts reveal information about their relative contribution. When electrostatic chain-surface attraction is present, the largest adsorbed masses are observed. However, significant mass is measured even when an electrostatic barrier to adsorption is present, suggesting the importance of forces of nonelectrostatic origin, which include both hydrophobic interactions and specific forces acting at short distances. This mechanism results in large adsorbed amounts for the adsorption of weak polyelectrolytes, and it is apparent especially in the adsorption behavior of a neutral polymer.

Immunocytotoxicity, cytogenotoxicity and genotoxicity of cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis.

There is an increased use of Quantum Dot (QDs) in biological and biomedical applications, but little is known about their marine ecotoxicology. So, the aim of this study was to investigate the possible immunocytotoxic, cytogenotoxic and genotoxic effects of cadmium telluride QDs (CdTe QDs) on the marine mussel Mytilus galloprovincialis. Mussels were exposed to 10 µg L(-1) of CdTe QDs or to soluble Cd [Cd(NO3)2] for 14 days and Cd accumulation, immunocytotoxicity [hemocyte density, cell viability, lysosomal membrane stability (LMS), differential cell counts (DCC)], cytogenotoxicity (micronucleus test and nuclear abnormalities assay) and genotoxicity (comet assay) were analyzed. Results show that in vivo exposure to QDs, Cd is accumulated in mussel soft tissues and hemolymph and induce immunotoxic effects mediated by a decrease in LMS, changes in DCC, as well as genotoxicity (DNA damage). However, QDs do not induce significant changes in hemocytes density, cell viability and cytogenetic parameters in opposition to Cd(2+). Soluble Cd is the most cytotoxic and cytogenotoxic form on Mytilus hemocytes due to a higher accumulation of Cd in tissues. Results indicate that immunotoxicity and genotoxicity of CdTe QDs and Cd(2+) are mediated by different modes of action and show that Mytilus hemocytes are important targets for in vivo QDs toxicity.

Proteomic response of mussels Mytilus galloprovincialis exposed to CuO NPs and Cu²âº: an exploratory biomarker discovery.

CuO NPs are one of the most used metal nanomaterials nowadays with several industrial and other commercial applications. Nevertheless, less is known about the mechanisms by which these NPs inflict toxicity in mussels and to what extent it differs from Cu(2+). The aim of this study was to investigate changes in protein expression profiles in mussels Mytilus galloprovincialis exposed for 15 days to CuO NPs and Cu(2+) (10 µg L(-1)) using a proteomic approach. Results demonstrate that CuO NPs and Cu(2+) induced major changes in protein expression in mussels' showing several tissue and metal-dependent responses. CuO NPs showed a higher tendency to up-regulate proteins in the gills and down-regulate in the digestive gland, while Cu(2+) showed the opposite tendency. Distinctive sets of differentially expressed proteins were found, either common or specific to each Cu form and tissue, reflecting different mechanisms involved in their toxicity. Fifteen of the differentially expressed proteins from both tissues were identified by MALDI-TOF-TOF. Identified proteins indicate common response mechanisms induced by CuO NPs and Cu(2+), namely in cytoskeleton and cell structure (actin, α-tubulin, paramyosin), stress response (heat shock cognate 71, putative C1q domain containing protein), transcription regulation (zinc-finger BED domain-containing protein 1, nuclear receptor subfamily 1G) and energy metabolism (ATP synthase F0 subunit 6). CuO NPs alone also had a marked effect on other biological processes, namely oxidative stress (GST), proteolysis (cathepsin L) and apoptosis (caspase 3/7-1). On the other hand, Cu(2+) affected a protein associated with adhesion and mobility, precollagen-D that is associated with the detoxification mechanism of Cu(2+). Protein identification clearly showed that the toxicity of CuO NPs is not solely due to Cu(2+) dissolution and can result in mitochondrial and nucleus stress-induced cell signalling cascades that can lead to apoptosis. While the absence of the mussel genome precluded the identification of other proteins relevant to clarify the effects of CuO NPs in mussels' tissues, proteomics analysis provided additional knowledge of their potential effects at the protein level that after confirmation and validation can be used as putative new biomarkers in nanotoxicology.

Effects of silver nanoparticles exposure in the mussel Mytilus galloprovincialis.

Silver nanoparticles (Ag NPs) have emerged as one of the most commonly used NPs in a wide range of industrial and commercial applications. This has caused increasing concern about their fate in the environment as well as uptake and potential toxicity towards aquatic organisms. Accordingly, mussels Mytilus galloprovincialis were exposed to 10 µg L(-1) of Ag NPs and ionic silver (Ag+) for 15 days, and biomarkers of oxidative stress and metal accumulation were determined. Accumulation results show that both Ag NPs and Ag+ accumulated in both gills and digestive glands. Antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were activated by Ag NPs and Ag+, showing different antioxidant patterns in both gills and digestive glands. Moreover, metallothionein was inducted in gills, directly related to Ag accumulation, while in the digestive glands only a small fraction of Ag seems to be associated with this protein. Lipid peroxidation was higher in gills exposed to Ag NPs, whereas in the digestive glands only Ag+ induced lipid peroxidation. Ag NPs and Ag+ cause oxidative stress with distinct modes of action and it's not clear if for Ag NPs the observed effects are attributed to free Ag+ ions associated with the nanoparticle effect.

Genotoxicity in two bivalve species from a coastal lagoon in the south of Portugal.

DNA damage was evaluated by comet assay in the haemolymph of two bivalve species Ruditapes decussatus and Mytilus galloprovincialis from the Ria Formosa lagoon (south Coast of Portugal). Clams and mussels were sampled from sites close to each other to determine interspecific responses to similar environmental conditions, considering also seasonal and gender differences. Coupled with genotoxic effect, another damage biomarker (lipid peroxidation) was analysed to verify if the conditions that instigate DNA damage can be related with injury to cell membranes. For both species, DNA damage was low, reflecting the low levels of genotoxic contaminants in the lagoon, and no interspecific differences were found. However, seasonal differences were established for both bivalve species, reflecting higher environmental stress in summer. Regarding gender susceptibility, only clams showed differences in percentage of Tail DNA, with females more sensitive to DNA damage than males. Additionally, results for clams point out that factors responsible for LPO may not be the same as those causing genotoxicity. This study demonstrated that DNA damage is a sensitive biomarker to discriminate spatial, temporal and gender differences, being an appropriate biomarker for genotoxicity evaluation even in places of low contamination, such as the Ria Formosa lagoon.

Differential protein expression in mussels Mytilus galloprovincialis exposed to nano and ionic Ag.

Ag NPs are one of the most commonly used NPs in nanotechnology whose environmental impacts are to date unknown and the information about bioavailability, mechanisms of biological uptake and toxic implications in organisms is scarce. So, the main objective of this study was to investigate differences in protein expression profiles in gills and digestive gland of mussels Mytilus galloprovincialis exposed to Ag NPs and Ag(+) (10 µg L(-1)) for a period of 15 days. Protein expression profiles of exposed gills and digestive glands were compared to those of control mussels using two-dimensional electrophoresis to discriminate differentially expressed proteins. Different patterns of protein expression were obtained for exposed mussels, dependent not only on the different redox requirements of each tissue but also to the Ag form used. Unique sets of differentially expressed proteins were affected by each silver form in addition to proteins that were affected by both Ag NPs and Ag(+). Fifteen of these proteins were subsequently identified by MALDI-TOF-TOF and database search. Ag NPs affected similar cellular pathways as Ag(+), with common response mechanisms in cytoskeleton and cell structure (catchin, myosin heavy chain), stress response (heat shock protein 70), oxidative stress (glutathione s-transferase), transcriptional regulation (nuclear receptor subfamily 1G), adhesion and mobility (precollagen-P) and energy metabolism (ATP synthase F0 subunit 6 and NADH dehydrogenase subunit 2). Exposure to Ag NPs altered the expression of two proteins associated with stress response (major vault protein and ras partial) and one protein involved in cytoskeleton and cell structure (paramyosin), while exposure to Ag(+) had a strong influence in one protein related to stress response (putative c1q domain containing protein) and two proteins involved in cytoskeleton and cell structure (actin and α-tubulin). Protein identification showed that Ag NPs toxicity is mediated by oxidative stress-induced cell signalling cascades (including mitochondria and nucleus) that can lead to cell death. This toxicity represents the cumulative effect of Ag(+) released from the particles and other properties as particle size and surface reactivity. This study helped to unravel the molecular mechanisms that can be associated with Ag NPs toxicity; nevertheless, some additional studies are required to investigate the exact interaction between these NPs and cellular components.

Accumulation and toxicity of copper oxide nanoparticles in the digestive gland of Mytilus galloprovincialis.

Given the wide use of CuO nanoparticles in various industrial and commercial applications they will inevitably end up in the aquatic environment. However, little information exists on their biological effects in bivalve species. Accordingly, mussels Mytilus galloprovincialis were exposed to 10 µg Cu L(-1) as CuO nanoparticles and Cu(2+) for 15 days, and biomarkers of oxidative stress (superoxide dismutase, catalase and glutathione peroxidase), damage (lipid peroxidation) and metal exposure (metallothionein) were determined along with Cu accumulation in the digestive glands of mussels. Cu was linearly accumulated with time of exposure in mussels exposed to CuO nanoparticles, while in those exposed to Cu(2+) elimination was significant by day 15. Both forms of Cu cause oxidative stress with distinct modes of action. Exposure to CuO nanoparticles induces lower SOD activity in digestive glands compared to those exposed to Cu(2+), while CAT was only activated after 7 days of exposure to nano and ionic Cu, with contradictory effects after 15 days of exposure and GPX activities were similar. Lipid peroxidation levels increased in both Cu forms despite different antioxidant efficiency. Moreover, a linear induction of metallothionein was detected with time in mussels exposed to CuO nanoparticles, directly related to Cu accumulation, whereas in those exposed to Cu(2+) metallothionein was only induced after 15 days of exposure. Since only a small fraction of soluble Cu fraction was released from CuO nanoparticles, the observed effects seem to be related to the nano form of Cu, with aggregation as a key factor. Overall, our results show that the digestive gland is susceptible to CuO nanoparticles related oxidative stress, and is also the main tissue for their accumulation.